1. Field of Invention
The invention relates to a measuring device having an invert measuring rod and a diameter measuring sleeve, for obtaining inlet invert measurements, pipe invert measurements, and pipe diameter measurements.
2. Description of the Related Art
Professionals in land surveying, municipal maintenance, and related industries often must obtain depth measurements of inlets, manholes, and other subsurface structures. Surveying professionals also often must obtain depth and diameter measurements of underground pipes leading to and from subterranean inlets or other subsurface structures. Surveying professionals refer to these depth measurements as “bottom elevation” measurements or, as used herein, “invert” measurements.
There are various methods and apparatus known for taking inlet invert measurements, pipe invert measurements, and pipe diameter measurements. For example, surveying professionals may physically enter an inlet to obtain inlet invert measurements, pipe invert measurements, and pipe diameter measurements. However, physically entering an inlet, such as a public sewer that might be covered by a manhole cover, or other subsurface structure, can be time consuming, cumbersome, and dangerous.
Another method to obtain an invert measurement includes dropping a tape measure or a staff-type device into an inlet. Yet another approach is to peer into the inlet from ground level, using a flashlight to locate an underground pipe and then to estimate visually the size of the underground pipe relative to a tape measure or a staff-type device.